stock tm m14 socom questions

[Darkmike]

ive got a standard tm m14 n want a couple of questions answering...

its on a budget tbh so just goin b prommy barrel when in stock n new tm bucking its just secondary for my l96 aswell as my usp

1.Using 0.2s or 0.25bbs on stock fps?

2.Lipo 7.4 or large 8.4 or small 9.6?

Cheers

Mike